Front vehicle body structures of the aforementioned type are known as disclosed in Patent Literature 1. In the front vehicle body structure disclosed in Patent Literature 1, each of the front side frames includes a bend portion (slanting portion) bent along the lower dashboard panel, a sub frame mount bracket and a plate member are mounted on the bend portion, and a nut member for mounting a sub frame (chassis frame) is supported by the sub frame mount bracket and the plate member.
According to the front vehicle body structure disclosed in Patent Literature 1, when a predetermined load has been input to the sub frame, the nut member is detached and dropped off the front side frame, so that the sub frame can be detached and dropped off the front side frame.
In the front vehicle body structure disclosed in Patent Literature 1, the nut member for mounting the sub frame is supported by the sub frame mount bracket and the plate member, and the sub frame is detached and dropped off the sub frame when a load of more than a predetermined level has been input to the sub frame. Therefore, when a frontal collision load has acted on the front side frames, this front vehicle body structure cannot cause the sub frame to generate a reactive force against the frontal collision force so as to buckle and deform the front side frames. As a consequence, absorption of impact energy of the frontal collision load tends to be insufficient.